This invention relates to air duct systems in buildings, and more particularly, to an air controller specifically for use in a ceiling vent, which forms a part of an air handling system.
In the prior art, it is known to mount air ducts above a drop ceiling, in the space between the ceiling and the roof or floor above. The roof or floor is supported by bar joists and the drop ceiling, in part, prevents heat build-up, particularly under conditions where there is a fire below the drop ceiling, and this prevents the bar joists from buckling and the floor above from collapsing. Of course, the dropped ceiling is only partially effective in this regard, and indeed, in those spaces where an air diffuser is provided across the end of an air duct passing through the ceiling, there is ready access to the space between the drop ceiling and the floor above for the hot air generated by the fire. It is known to provide such openings with a heavy steel door having asbestos on both sides, said door being supported by a wire having a fusible link therein which allows the wire to separate under elevated temperatures and allows the door to close once it has separated.
It is my desire by this invention to improve the effectiveness of hot air control under fire conditions by providing a plurality of curtain-type fire dampers mounted in such a way as to provide a buffer space therebetween and greatly reduce the heat build-up between the dropped ceiling and the floor above.